Design of plasmonic Ag-TiO2/H3PW12O40 composite film with enhanced sunlight photocatalytic activity towards o-chlorophenol degradation

Abstract

A series of plasmonic Ag-TiO2/H3PW12O40 composite films were fabricated and immobilized by validated preparation technique. The chemical composition and phase, optical, SPR effect and pore-structure properties together with the morphology of as-prepared composite film are well-characterized. The multi-synergies of as-prepared composite films were gained by combined action of electron-capture action via H3PW12O40, visible-response induced by Ag, and Schottky-junction formed between TiO2-Ag. Under simulated sunlight, the maximal K app of o-chlorophenol (o-CP) reached 0.0075 min−1 which was 3.95-fold larger than that of TiO2 film, while it was restrained obviously under acid condition. In the photocatalytic degradation process, ·OH and ·O2 − attacked preferentially ortho and para position of o-CP molecule, and accordingly the specific degradation pathways were speculated. The novel composite film exhibited an excellent applicability due to self-regeneration of H3PW12O40, well-protection of metal Ag° and favorable immobilization.

ZnO/Cu2O/Si Nanowire Arrays as Ternary Heterostructure-Based Photocatalysts with Enhanced Photodegradation Performances

“…Examinations of possible photocatalytic mechanism of ZCS heterostructures were carried out based on the trapping tests of active scavengers [27, 28]. Na 2 -EDTA, AgNO 3, and IPA were engaged to trap the photogenerated holes (h + ), electrons (e − ) and hydroxyl radicals (·OH) in the solutions, respectively, as demonstrated in Fig.…”

PHOTOCATALYTIC DEGRADATION OF MULTIPLE CHLOROPHENOLS AS SIMULATED ENVIRONMENTAL POLLUTANTS IN TiO2/H3PW12O40/AG COMPOSITE FILM SYSTEM

“…As-prepared TiO2/H3PW12O40/Ag film showed the excellent photocatalytic property, the results showed that Kapp of as-prepared TiO2/H3PW12O40/Ag reaction system increased significantly in comparison with TiO2 system (P < 0.05). Because TiO2/H3PW12O40/Ag reaction system delayed the recombination of holes and electrons pairs efficiently owing to the synergistic effects between the Keggin unit and TiO2 and the generation of Schottky junction at the interface between Ag and TiO2, meanwhile expanded the absorption of visible-light due to SPR effect (Lu et al, 2017). It is worth noting that only a limited amount of ca.…”

“…It is well known that •OH is a very strong activator as well as ortho-and para-directing in electrophilic aromatic substitution (Antonaraki et al, 2002). Therefore, •OH radical that was confirmed as the main role in TiO2/H3PW12O40/Ag reaction system (Lu et al, 2017) can directly attack the electron-rich positions in CPs molecules with a rapid degradation rate.…”

“…The combining process of sol-gel-hydrothermal route and temperature programming was employed to fabricate TiO2/H3PW12O40/Ag composite film, which has been described in our previous study (Lu et al, 2017). The as-prepared film was confirmed with anatase phase TiO2, the intact saturation Keggin structure, and metallic Ag inserted into the pore structures of TiO2/H3PW12O40, which enhanced the quantum efficiency, visible-light absorption and further improving in the photocatalytic performance.…”

“…In our previous work, an efficient plasmonic TiO2/H3PW12O40/Ag composite film was fabricated with an enhanced solar light photocatalytic activity due to the combined actions of electrons-trapping via H3PW12O40, visible-response induced by Ag, and Schottkyjunction formed between TiO2 and Ag (Lu et al, 2017). It has been documented that the chlorine positions in chlorophenol homologues act an important role in its photodegradation kinetics (Hugül et al, 2000;Czaplicka et al, 2006).…”